derby.storage.initialPages

Function

The on-disk size of a
Derby table grows by one page
at a time until eight pages of user data (or nine pages of total disk use; one
is used for overhead) have been allocated. Then it will grow by eight pages at a
time if possible.

A Derby table or index can
be created with a number of pages already pre-allocated. To do so, specify the
property prior to the CREATE TABLE or CREATE INDEX statement.

Define the number of user pages the table or index is to be created with.
The purpose of this property is to preallocate a table or index of reasonable
size if the user expects that a large amount of data will be inserted into
the table or index. A table or index that has the pre-allocated pages will
enjoy a small performance improvement over a table or index that has no
pre-allocated pages when the data are loaded.

The total desired size of the table or index should be the following number
of bytes:

(1 + derby.storage.initialPages) * derby.storage.pageSize

When you create a table or an index after setting this property,
Derby attempts to preallocate
the requested number of user pages. However, the operations do not fail even if
they are unable to preallocate the requested number of pages, as long as they
allocate at least one page.